1. Technical Field
The present invention relates to a semiconductor chip whose purpose is to suppress an increase in the resistance of a wire that interconnects a solar cell and a secondary cell and particularly relates to a semiconductor chip that has a feature in the layout of external connection terminals disposed on the semiconductor chip.
Further, the present invention relates to a solar system including a semiconductor chip.
2. Related Art
Japanese Patent Application Laid-Open (JP-A) No. 8-251818 discloses a charging control system having the function of controlling charging from a solar cell to a secondary cell. The charging control system is equipped with a solar cell, a secondary cell, a wire that electrically interconnects the solar cell and the secondary cell, and a backflow prevention section that is disposed on the wire and prevents backflow of electric current from the secondary cell to the solar cell.
Here, the charging control system suggested particularly from FIG. 1 of JP-A No. 8-251818 will have the configuration shown in FIG. 4. The charging control system shown in FIG. 4 is equipped with a solar cell 1, a secondary cell 2, and a semiconductor chip 3. The semiconductor chip 3 is equipped with a first terminal 4 that is electrically connected to the solar cell 1, a second terminal 5 that is electrically connected to the secondary cell 2, a wire 6 that electrically interconnects the first terminal 4 and the second terminal 5, and a backflow prevention section 7 that is formed on the wire 6 and prevents backflow of electric current from the secondary cell 2 to the solar cell 1.
However, as shown in FIG. 4, it is common in recent years that, in addition to the backflow prevention section 7, circuits and so forth having various functions are consolidated as internal circuits 8 on the semiconductor chip 3 used in the charging control system.
Consequently, when the charging control system is given a configuration where the wire 6 that electrically interconnects the solar cell 1 and the secondary cell 2 extends from one side of the semiconductor chip 3 to another side opposing that one side like in the semiconductor chip 3 used in the conventional charging control system shown in FIG. 4, the wire 6 becomes lengthy because it is dependent on the size of the internal circuits 8, and the wire resistance ends up increasing in correspondence thereto. For this reason, there is the fear that the charging control system will suffer electrical loss in the case of performing charging from the solar cell 1 to the secondary cell 2.